1 84 POPULAR LECTURES AND ADDRESSES. 



seems to have been proved that at least some 

 sensible part of the light of the " corona " is a 

 terrestrial atmospheric halo or dispersive reflection 

 of the light of the glowing hydrogen and 

 " helium " 1 round the sun. I believe I may say. 

 on the present occasion, when preparation must 

 again be made to utilise a total eclipse of the Sun, 

 that the British Association confidently trusts to 

 our Government exercising the same wise liberality 

 as heretofore in the interests of science. 



The old nebular hypothesis supposes the solar 

 system and other similar systems through the 

 universe which we sec at a distance as stars, 

 to have originated in the condensation of fiery 

 nebulous matter. This hypothesis was invented 

 before the discovery of thermodynamics, or the 

 nebulae would not have been supposed to be fiery ; 

 and the idea seems never to have occurred to any 

 of its inventors or early supporters that the matter, 

 the condensation of which they supposed to consti- 



1 Krankland and I.orkyer find the yellow pnuninenees lo <^ive a 

 very decided bright line not far from I), hut hitherto not identified 

 with any terrestrial flame. It seems to indicate a new substance, 

 which they propose to call Helium. 



